Glass fiber drawing mechanism



y 29, 1956 J. F. COURTNEY m; 2,747,335

GLASS FIBER DRAWING MECHANISM Filed April 18, 1951 United States Patent GLASS FIBER DRAWING MECHANISM Joseph F. Courtney, Chicago, and Adelbert C. Radtke', Oak Park, Ill., assignors to International Harvester Company, a corporation of New Jersey Application April 18, 1951, Serial No. 221,596

4 Claims. (CI. 49-17) This invention relates to means forattenuating thermoplastic material and has particular reference to the manufacture of glass fiber strands and the like.

In the production of such strands, molten glass is drawn into a plurality of fine filaments which are individually coated with a bonding agent and then gathered in parallel to for-ma strand while the coating is still fluid or adherent so that the coatings on contiguous filaments may coalesce-and thus hold the filaments together.

It Will be observed that each filament is only several microns in diameter and that normally several hundred filaments having a collective tensile strength of a few pounds are grouped into-a strand. The diameter, texture and flexibility of the filaments are in part determined by the natureofattenuation, and it has been established that to "obtain satisfactory characteristics the filaments must be drawn at present at a rate of approximately ten thousand feet per minute and be devoid of transverse deformation.

In view of the extremely fast drawing rate and the fragility and low tensilestrength of the material involved, considerable difliculty has been encountered in provid- :ing a satisfactory drawing mechanism.

Arrangements heretofore considered practical contemplated grasping the strand between opposed rolls or winding it on a rotating mandrel. The former has proved objectionable in that it obtains approximately line contact with the strand and thus concentrates opposing pressures which effect transverse deformation of the strand and frequently cause unset coating to exude from between the filaments so that they are exposed to abrade against each other. The high pressure necessary to obtain a positive grasp on the strand, at times also causes the coating, which is preferably a plastic, to adhere to the rolls and peel oif the filaments. In addition, because of the small areas of engagement of the rolls with the strand, slippage of a roll is inherent and apt to fray the material.

Winding directly on a mandrel produces a constantly changing drawing rate in that as successive layers are deposited, the peripheral speed of the surface on which each succeeding layer is wound increases, thus drawing filaments of continuously shrinking diameter and changing texture. In such an arrangement, the pressure of overlaying windings is cumulative and may be of sufficient magnitude to cause permanent deformation of the strand or at least adherence between or fracture of the coatings on contacting or crossing windings.

Other mechanisms proposed have failed to provide a positive drawing attitude or required uniformity of operation.

A general object of the invention is to provide simple, novel drawing means which obviate the disadvantages incident to those heretofore available.

A further object is to devise means which will effect the necessary pull on the fibers without imposing high transverse stresses.

. Patented May 29, 1956 ice The invention contemplates the provision of means designed to obtain a gentle grasp or pressure on the strand over an extensive area thereof whereby the cumulative elfort provides a sufiicient hold on the strand for drawing without deforming or otherwise injuring the strand.

A different object is to provide drawing means which will maintain a substantially uniform pulling rate and apply it to the strand in such a manner as to prevent its breakage.

Amore specific object is to devise drawing means providing extensive frictional contact with the strand along a smooth curved or sinuous flow path whereby a positive pulling effect is established without imposing high transverselpress ures on the strand.

These and other objects of the invention will become more apparent from the specification and the drawings wherein:

Figures 1 to 3 illustrate a preferred-embodiment of the invention, Figure 1 being a side elevational view thereof, Figure 2 a fragmentary enlarged sectional view of the drawing wheel taken substantially on the line -2-2 of Figure 3, and Figure 3 a fragmentary enlarged side elevational view of the wheel.

Referring now to the embodiment of the invention illustrated in Figures '1 to 3, the furnace 2 comprises a die plate 4 through which the-upstream ends of the filaments 10 are issued in a fan arrangement over the applicator assembly 12 which may be movably supported on a stand 150, directly below the furnace, the filaments then being passed under the gathering sheave 16 which may be journaled at 20 to the frame below the applicator assembly. The strand 18 which discharges from the sheave is extended diagonally upwardly (although it may extend horizontally) and entered at the bottom of wheel -22and is trained thereon. The strand is entered on the surface 24 adjacent to the outer periphery thereof and as it travels around the wheel 22 it eventually slides or progresses into the inner apex of the V-shapcd groove 32. It will be seen that the strand engages the wheel 22 along substantially 270 and the points of entry of the strand on the wheel 22 and the discharge of the strand with respect to the wheel 22 are laterally and radially separated so that the strand may cross without engagement. In the present embodiment, the wheel 22 is driven by a shaft 152 which may be an extension of the armature shaft of the drive motor 44. The strand 18 is pressed against the wheel 22 by means of an idler roll 154 biased against the strand 18 adjacent to its point of discharge from the wheel 22, said roll 154 being journaled as at 156 to one end of an arm 158, the other end of the arm being fulcrumed to any suitable support as at 160. The arm 158 is biased in a direction engaging the roll 154 with the strand by means of a tension spring 162 which at one end is connected to the arm 158 intermediate the ends thereof as at 164 and at the other end to a fixed suitable support 166. Disengaging means 168 may be connected at one end as at 170 to the lever 158 intermediate the ends thereof adjacent to roller 154 and at the opposite end to actuating means of any convenient form such as for example a cable or chain linkage. The downstream end of the strand is initially permitted to discharge on the ground or into any auxiliary container until the rotation of the wheel 22 is at the rated speed and the strand 18 is being drawn to desired size. As soon as the strand is of desired characteristics the nozzle N is assembled and actuated to provide the tensile force on the strand which is slightly greater than the discharge rate of the strand from the wheel 22 whereby the strand is caused to strip from the wheel and to be snubbed thereagainst. Substantially simultaneously with activation of the nozzle, the roller 154 is disengaged from the wheel 22. The desired strand is deposited into the container 74, the initial portion being snipped therefrom and discarded. In addition to the hold on the strand due to friction developed between the strand and the contacting surfaces of the groove, an accompanying suction force may be employed to augment this action and may be realized by providing a plurality of circumferentially spaced preferably radially arranged inlet openings 172, 172 leading inwardly from the apex of the groove, each inlet opening continuing at its inner extremity into the in ner end of a diametrically larger passageway 174 disposed inwardly of and preferably paralleling the surface 24 and providing an outlet 176 at its radially outer extremity at the outer periphery of flange 26. These passages are preferably raked or swept back with respect to the direction of rotation of the drawing wheel. Due to the centrifugal action of the arrangement and disposition and relationship of the passages, the air is sucked in at the inlet openings 172 whereby urging the strand against the drawing wheel. To effect easy stripping, a valve member such as a flapper or a closure Wheel 178 may be rotatably mounted in position to close the outlet 176 of each passage when the related inlet thereof and portion of the strand is at the discharge area.

It will be observed that several furnaces may be employed in conjunction with the drawing means and the filaments from each furnace may be gathered into a single strand in the embodiments described.

What is claimed is:

1. In a device for attenuating elongatable material such as glass strand, a rotatable disc-like element comprising axially spaced annular portions defining a V- shaped peripheral groove therebetween and presenting a drawing surface along opposite sides of the groove about one of which a strand is adapted to be trained, and means for creating suction at the apex of the groove for drawing the strand thereinto and comprising internal passages in at least one of said portions and each passage having an inlet open to the apex of the groove and an outlet disposed farther from the axis of rotation of said element than the inlet.

2. A device for attenuating elongatable material such as glass strand and the like, a rotatable circular element comprising an annular material-engaging drawing face,

means for obtaining suction through said face for bold ing the material thereagainst and comprising an annular portion on said element extending radially outwardly of said'face and provided with a series of passages having inlets open through said face and having outlets, said outlets disposed farther outwardly from the axis of rotation of said element than said inlets, and means for stopping the suction positioned in selective closing relationship to said outlets.

3. A device for attenuating elongatable material such as glass strand and the like, a rotatable circular cylinder comprising peripheral material engaging drawing face, means for obtaining suction through said face for holding the material thereagainst and comprising rigid means on said cylinder extending radially outwardly of said face and provided with a series of passages having inlets open through said face and having outlets, said outlets disposed farther outwardly from the axis of rotation of said cylinder than said inlets.

4. A device according to claim 3 and said passages being raked back with respect to the direction and rotation of said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,067,251 Taylor Jan. 12, 1937 2,133,238 Slayter et al Oct. 11, 1938 2,150,945 Slayter Mar. 21, 1939 2,206,060 Slayter July 2, 1940 2,224,466 Baker et al Dec. 10, 1940 2,239,722 Lannan et al. Apr. 29, 1941 2,291,873 Brubaker Aug. 4, 1942 2,411,660 Manning Nov. 26, 1946 2,418,873 Fletcher et al Apr. 15, 1947 2,448,499 Swann Aug. 31, 1948 2,460,899 Modigliani et al. Feb. 8, 1949 2,526,775 Slayter et al. Oct. 24, 1950 2,607,167 Brenner Aug. 19, 1952 FOREIGN PATENTS 359,627 Great Britain Oct. 29, 1931 525,283 Great Britain Aug. 26, 1940 

